This invention relates generally to improvements in spray nozzles for irrigation sprinklers. More particularly, this invention relates to a sprinkler nozzle construction designed to produce a highly controllable and enhanced water stream spray pattern for achieving significantly improved short range or close-in distribution of water for irrigating vegetation and the like positioned relatively close to the sprinkler.
In a typical irrigation system, a plurality of sprinklers are provided for distributing irrigation water in a plurality of overlapping stream spray patterns for irrigating a selected terrain area. These sprinklers may include rotatably driven or so-called fixed spray heads each including one or more spray nozzles designed for outward projection of respective water streams over a designated part-circle or full-circle terrain area. Since the distribution of irrigation water for each water stream is typically nonuniform over the projected range thereof, overlapping water stream spray patterns are normally provided in an attempt to improve the overall uniformity of water distribution throughout the irrigated terrain area.
In this regard, significant design effort has been directed to the provision of a sprinkler spray nozzle capable of providing a predetermined and controllable distribution of irrigation water throughout the range of the projected water stream. A wide variety of different spray nozzle configurations have been developed for enhancing or increasing the maximum range, thereby permitting a specified terrain area to be irrigated by a reduced number of sprinklers. In general, however, sprinkler spray nozzles have not provided for adequate short range or close-in distribution for irrigating a terrain zone typically within about 1½ feet from the sprinkler. As a result, this close-in terrain zone and associated vegetation located therein can be inadequately irrigated.
Improved sprinkler spray nozzles have been designed with the intent to provide enhanced close-in water distribution. For the most part, such nozzle designs have envisioned the use of multiple nozzles or nozzle outlets, at least one of which is specially contoured to provide a distorted or low pressure spray pattern so that a greater proportion of the outwardly projected water stream will fall to the ground at a location closer to the sprinkler. See, for example, U.S. Pat. Nos. 5,240,182; 5,240,184; 5,598,977; 5,642,861; and 5,299,742. In another design, a single composite nozzle passage is provided to produce a relatively high velocity stream segment for long range irrigation and a comparatively lower velocity stream segment for short range or close-in irrigation. See, for example, U.S. Pat. No. 5,676,315. While spray nozzle configurations have achieved improvements in close-in water distribution, adequate and satisfactory close-in delivery of irrigation water to a terrain zone immediately adjacent the sprinkler continues to be a problem. In addition, in many such spray nozzles, the close-in water distribution takes the form of relatively high velocity water droplets which can undesirably erode and wash away or otherwise disturb newly planted seed., such as grass seed used in a newly planted lawn.
There exists, therefore, a need for further improvements in and to sprinkler spray nozzles, particularly with respect to providing enhanced short range or close-in distribution of irrigation water. Moreover, there exists a need to provide such improved close-in water distribution in the form of relatively small, relatively low velocity water droplets which do not disturb newly planted seed. The present invention fulfills these needs and provides further related advantages.